---
title: "Claude Fable 5 support"
date: "2026-06-10"
---

## Claude Fable 5 support

Fabro now includes Anthropic's `claude-fable-5` in the built-in model catalog, with `fable` and `claude-fable` aliases. It supports the model's 1M context window, 128K max output, vision, tools, prompt caching, and native `reasoning_effort` levels without changing the default Anthropic model from `claude-sonnet-4-6`.

Fable refusals are now handled through Fabro's provider-neutral fallback system. When Anthropic returns `stop_reason: "refusal"`, Fabro surfaces a content-filter LLM error with the refusal detail preserved and retries through `run.model.fallbacks` when configured.

## More

<Accordion title="Models">
- Added `claude-fable-5` to the Anthropic catalog at $10 / $50 per MTok input/output pricing
- Added aliases `fable` and `claude-fable`
- Kept `claude-sonnet-4-6` as the Anthropic default
- Omitted deprecated Anthropic sampling parameters for Fable requests
</Accordion>

<Accordion title="Fallbacks">
- Fable refusal responses now participate in configured model fallback chains
- Refusals without a configured fallback surface as clear LLM content-filter errors
</Accordion>
